@Joe Villeneuve hopefully this will help. Here is a list of the inputs I have so far (numbers are for example purposes only):
I then calculate ALL combinations of these values; 485099 different combinations. Of those combinations, 426 will meet the minimum requirements (8% minimum ROI, $300/mo. cash flow). I can now look to see which combination of inputs will maximize my cash flow:
Looks like I can't spend more than $2000 on the rehab and I need to put 25% down with a 3% interest rate.
But if I want to maximize ROI, I need to minimize the rehab and only put 15% down (assuming I can get max rent), with max ROI at 10%
It also shows that I can't go below $1750 on rent with no rehab to still meet my requirements:
Of course, any analysis is only as good as your inputs and the quality of any assumptions, and "optimization" is based on actual goals for any deal but at least I know my limits for negotiating.
Sorry @David Parathundil but this calculator still needs some work before I can let anyone use it - only the outputs are in an excel spreadsheet. I'm trying to gauge if there would be an interest in this type of tool.